The present invention relates to a blister pack, consisting of a perforated lower plastic backing part, or bottom foil, and an upper, cut plastic foil part, or cover foil, the cover foil conforming closely the packaged article placed between the parts and being connected with the backing part all around the article by heat sealing, where the bottom foil and the cover foil are both made of the same type of plastic.
Such a pack is disclosed in German Published, Non-Examined Patent Application DE-OS 26 22 625, and is composed of a foam foil provided as the bottom foil and a single foil or compound foil provided as the cover foil. When using a compound foil as the cover foil, the cover foil layer which faces the foam foil and which is heat sealable as well as the foam foil itself consist of or contain the same basic material, such as polyethylene (PE) or polyvinyl chloride (PCV), in order to achieve good adhesion.
A similar pack is disclosed in German Published, Non-Examined Patent Application DE-OS 29 51 226. Here, too, the cover foil and the bottom foil are made of the same plastic material, e.g. SURLYN.TM. marketed by E. I. DuPont de Nemours & Co. An information carrier, for example a printed slip of paper, is inserted in an edge area of the pack and has a cover on one side which makes a solid connection with one of the foils, so that this information carrier can be used as a tear strip if it extends past the edges of the two foils.
Disposal of the materials used in blister packs of the type described is an increasing problem.